FreeBSD/Linux Kernel Cross Reference
sys/netinet6/ip6_etherip.c

     /*      $NetBSD: ip6_etherip.c,v 1.11.4.1 2010/11/21 20:45:39 riz Exp $        */
     
     /*
      *  Copyright (c) 2006, Hans Rosenfeld <rosenfeld@grumpf.hope-2000.org>
      *  All rights reserved.
      *
      *  Redistribution and use in source and binary forms, with or without
      *  modification, are permitted provided that the following conditions
      *  are met:
     *  1. Redistributions of source code must retain the above copyright
     *     notice, this list of conditions and the following disclaimer.
     *  2. Redistributions in binary form must reproduce the above copyright
     *     notice, this list of conditions and the following disclaimer in the
     *     documentation and/or other materials provided with the distribution.
     *  3. Neither the name of Hans Rosenfeld nor the names of his
     *     contributors may be used to endorse or promote products derived
     *     from this software without specific prior written permission.
     *
     *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     *  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     *  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     *  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     *  SUCH DAMAGE.
     *
     *
     * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
     * All rights reserved.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the project nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: ip6_etherip.c,v 1.11.4.1 2010/11/21 20:45:39 riz Exp $");
    
    #include "opt_inet.h"
    #include "bpfilter.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/socket.h>
    #include <sys/sockio.h>
    #include <sys/mbuf.h>
    #include <sys/device.h>
    #include <sys/errno.h>
    #include <sys/ioctl.h>
    #include <sys/syslog.h>
    #include <sys/protosw.h>
    #include <sys/kernel.h>
    
    #include <net/if.h>
    #include <net/route.h>
    
    #include <netinet/in.h>
    #include <netinet/in_systm.h>
    #ifdef INET
    #include <netinet/ip.h>
    #endif
    #ifdef INET6
    #include <netinet/ip6.h>
    #include <netinet6/ip6_var.h>
    #include <netinet6/ip6_private.h>
    #include <netinet6/in6_var.h>
    #include <netinet6/ip6_etherip.h>
    #endif
    
    #include <net/if_ether.h>
    #include <net/if_media.h>
    #include <net/if_etherip.h>
    #if NBPFILTER > 0
    #include <net/bpf.h>
    #endif
   
   #include <machine/stdarg.h>
   
   int
   ip6_etherip_output(struct ifnet *ifp, struct mbuf *m)
   {
           struct rtentry *rt;
           struct etherip_softc *sc = (struct etherip_softc *)ifp->if_softc;
           struct sockaddr_in6 *sin6_src, *sin6_dst;
           struct ip6_hdr *ip6;    /* capsule IP header, host byte ordered */
           struct etherip_header eiphdr;
           int proto, error;
           union {
                   struct sockaddr         dst;
                   struct sockaddr_in6     dst6;
           } u;
   
           sin6_src = (struct sockaddr_in6 *)sc->sc_src;
           sin6_dst = (struct sockaddr_in6 *)sc->sc_dst;
   
           if (sin6_src == NULL || 
               sin6_dst == NULL ||
               sin6_src->sin6_family != AF_INET6 ||
               sin6_dst->sin6_family != AF_INET6) {
                   m_freem(m);
                   return EAFNOSUPPORT;
           }
   
           /* reset broadcast/multicast flags */
           m->m_flags &= ~(M_BCAST|M_MCAST);
   
           m->m_flags |= M_PKTHDR;
           proto = IPPROTO_ETHERIP;
   
           /* fill and prepend Ethernet-in-IP header */
           eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
           eiphdr.eip_pad = 0;
           M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
           if (m == NULL)
                   return ENOBUFS;
           if (M_UNWRITABLE(m, sizeof(struct etherip_header))) {
                   m = m_pullup(m, sizeof(struct etherip_header));
                   if (m == NULL)
                           return ENOBUFS;
           }
           memcpy(mtod(m, struct etherip_header *), &eiphdr, 
                  sizeof(struct etherip_header));
           
           /* prepend new IP header */
           M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
           if (m && m->m_len < sizeof(struct ip6_hdr))
                   m = m_pullup(m, sizeof(struct ip6_hdr));
           if (m == NULL)
                   return ENOBUFS;
   
           ip6 = mtod(m, struct ip6_hdr *);
           ip6->ip6_flow = 0;
           ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
           ip6->ip6_vfc |= IPV6_VERSION;
           ip6->ip6_nxt  = proto;
           ip6->ip6_hlim = ETHERIP_TTL;
           ip6->ip6_src  = sin6_src->sin6_addr;
   
           /* bidirectional configured tunnel mode */
           if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
                   ip6->ip6_dst = sin6_dst->sin6_addr;
           else  {
                   m_freem(m);
                   return ENETUNREACH;
           }
   
           sockaddr_in6_init(&u.dst6, &sin6_dst->sin6_addr, 0, 0, 0);
           if ((rt = rtcache_lookup(&sc->sc_ro, &u.dst)) == NULL) {
                   m_freem(m);
                   return ENETUNREACH;
           }
           /* if it constitutes infinite encapsulation, punt. */
           if (rt->rt_ifp == ifp) {
                   rtcache_free(&sc->sc_ro);
                   m_freem(m);
                   return ENETUNREACH;     /* XXX */
           }
   
           /*
            * force fragmentation to minimum MTU, to avoid path MTU discovery.
            * it is too painful to ask for resend of inner packet, to achieve
            * path MTU discovery for encapsulated packets.
            */
           error = ip6_output(m, 0, &sc->sc_ro, IPV6_MINMTU, NULL, NULL, NULL);
   
           return error;
   }
   
   int
   ip6_etherip_input(struct mbuf **mp, int *offp, int proto)
   {
           struct mbuf *m = *mp;
           int off = *offp;
           struct etherip_softc *sc;
           const struct ip6_hdr *ip6;
           struct sockaddr_in6 *src6, *dst6;
           struct ifnet *ifp = NULL;
           int s;
   
           if (proto != IPPROTO_ETHERIP) {
                   m_freem(m);
                   IP6_STATINC(IP6_STAT_NOGIF);
                   return IPPROTO_DONE;
           }
   
           ip6 = mtod(m, const struct ip6_hdr *);
   
           /* find device configured for this packets src and dst */
           LIST_FOREACH(sc, &etherip_softc_list, etherip_list) {
                   if( !sc->sc_src || !sc->sc_dst)
                           continue;
                   if (sc->sc_src->sa_family != AF_INET6 ||
                       sc->sc_dst->sa_family != AF_INET6)
                           continue;
   
                   src6 = (struct sockaddr_in6 *)sc->sc_src;
                   dst6 = (struct sockaddr_in6 *)sc->sc_dst;
   
                   if (!IN6_ARE_ADDR_EQUAL(&src6->sin6_addr, &ip6->ip6_dst) ||
                       !IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr, &ip6->ip6_src))
                           continue;
   
                   ifp = &sc->sc_ec.ec_if;
                   break;
           }
   
           /* no matching device found */
           if (!ifp) {
                   m_freem(m);
                   IP6_STATINC(IP6_STAT_ODROPPED);
                   return IPPROTO_DONE;
           }
   
           m_adj(m, off);
   
           /*
            * Section 4 of RFC 3378 requires that the EtherIP header of incoming
            * packets is verified to contain the correct values in the version and
            * reserved fields, and packets with wrong values be dropped.
            *
            * There is some discussion about what exactly the header should look
            * like, the RFC is not very clear there. To be compatible with broken
            * implementations, we don't check the header on incoming packets,
            * relying on the ethernet code to filter out garbage.
            *
            * The header we use for sending is compatible with the original
            * implementation in OpenBSD, which was used in former NetBSD versions
            * and is used in FreeBSD. One Linux implementation is known to use the
            * same value.
            */
           m_adj(m, sizeof(struct etherip_header));
           m = m_pullup(m, sizeof(struct ether_header));
           if (m == NULL) {
                   ifp->if_ierrors++;
                   return IPPROTO_DONE;
           }
   
           m->m_pkthdr.rcvif = ifp;
           m->m_flags &= ~(M_BCAST|M_MCAST);
   
   #if NBPFILTER > 0
           if (ifp->if_bpf)
                   bpf_mtap(ifp->if_bpf, m);
   #endif
   
           ifp->if_ipackets++;
   
           s = splnet();
           (ifp->if_input)(ifp, m);
           splx(s);
   
           return IPPROTO_DONE;
   }

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